Bank earnings have never been more complicated

FORTUNE — You would think that a well-researched and insightful book about the Washington legislative process would have nothing in common with a big bank’s quarterly earnings news release. But you’d be wrong.

If you read the two documents almost back to back — as I’ve done recently — you discover that the book and the earnings report offer insights into each other.

The book, Act of Congress: How America’s Essential Institution Works, and How it Doesn’t, by Bob Kaiser of the Washington Post, describes in great detail the way that the huge, cumbersome, and confusing (at least to me) Dodd-Frank financial reform bill came to be. The earnings release and supplements, issued on Monday by CitigroupC, total 101 pages by my unofficial count. They’re so complicated, cumbersome, jargon-laden, and confusing that they give you an insight into the problem that Dodd-Frank was trying to address: reforming institutions that are enormously big, and wildly complex.

In any number of cases, as we’ve seen — the “London Whale” trading loss suffered by JPMorgan Chase JPM is a classic example — executives of even well-run firms have no idea what’s going on in the bowels of their own institution until it’s too late.

You want to try to write laws to regulate an institution like that? Good luck to you.

Combine that with the political paralysis afflicting Congress — something that Kaiser, a Washington lifer (and a friend of mine) describes in great detail — and you see why Dodd-Frank had such a long and agonizing gestation.

I loved Kaiser’s descriptions of the endless negotiations among the various political players in Dodd-Frank, and especially the details of the negotiations and maneuvers by their staffers. Kaiser, as he makes it clear from the start, has been friendly with some of the players for years and cut a deal with them early in the game to get access to deep-inside information for his book.

That access lends Act of Congress a wealth of detail and description that you rarely see in non-fiction books. It’s easy to provide dramatic detail in fiction, all you have to do is make it up. But to provide real-life drama: That’s really tough, and Kaiser does it really well.

To say that the Citi earnings release and supplementary data are complicated is as understated as calling Yankee closer Mariano Rivera a reasonably competent pitcher.

The headline on Citi’s news release — the part of the package presumably aimed at a general audience — reads as follows: “Citigroup Reports Second Quarter 2013 Earnings per Share of $1.34; $1.25 Excluding CVA/DVA.” There’s a footnote (1) after “CVA/DVA,” and an explanation later on, but I still can’t translate either term into language approaching English.

I’m not blaming Citi’s public relations or investor relations people for distributing gibberish and sowing confusion. They do what they’re supposed to do, and what their superiors (and legal departments) are willing to sign off on. And presumably what Wall Street is interested in seeing.

But I sure wouldn’t want to be a Congressional or Senate staffer — or worse, a Congressman or Senator, who, unlike the staffers, aren’t specialists — having to deal with this kind of stuff in any detail.

Even something that sounds simple — like the Volcker Rule — is impossible, in my humble opinion, to define and enforce in any reasonable way. The rule, named for former Federal Reserve Chairman Paul Volcker, says that banks can buy securities for their own account in order to make markets for their customers, but they can’t buy securities for their own account in an attempt to make money. Good luck in figuring out a clear, simple, and enforceable distinction between trading for the purposes of making markets, and trading for the sake of trading. No one has come up with it yet, and Dodd-Frank is three years old.

I’m not any sort of Washington junkie, despite the Washington Post having run my work for about 20 years, but I had a fine, enlightening time reading Kaiser’s book and learning from it. Citi’s earnings release? Not so much.